James w



(No Modem J. W. DSTIN.

SAFETY DEVIGE EOE ELEVATOES.

Patented Nov. 27, 18.88..

WITWESSES ,EZu/L'n, @9u/L:

KNrrnn STATES PATENT Ormes.

JAMES IV. DUS'IIN, OF CONOWINGO, ASSIGNOR TO CHARLES C. CALDVELL,

' OF LIBERTY GROVE, MARYLAND.

SAFETY DEVICE FOR ELEVATOFRS.

SPECIFICATION forming part of Letters Patent No. 393.425. dated November 27, 1888.

Application filed June 13, i887. Serial No. 241,108. (No model.)

To all whom, it may concern.'

Be it known that I, JAMES W. DUsTrN, a citizen of the United States, residing at Gonowingo, in the county of Cecil and State of Maryland, have invented certain new and useful Improvements in Safety Devices for Elevators; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art'to which it appertains to make and use the same.

My invention relates to a safety device lor clevators to prevent them falling in case the hoisting-cable should break or Vsuddenly slacken.

The object of the invention is to provide a i simple and efficient device which will instant-ly lock the car at any point of its travel before said car and its load can have time to acquire a momentum. In most safety-clutches they are so arranged that the rack is directly cngaged by vthe clutch, and the latter has to make considerable sweep before it can lock the car. The time lost in this action is sufficient to allow the car to drop thedist-ance of oneor more cogs before the clutch comes into active engagement with the rack. The momentum of the car acquired in this time when loaded is enormous, andthe cogs are liable to be broken oft' or the clutch itself impaired. The importance,therefore,of instantaneously locking the car will be appreciated. In other forms where an idle-wheel gearing with a side rack is used the clutch is normally held so far from the idle-wheel thatitconsumes time in coming into engagement with said wheel when the moment of danger arrives.

My invention consists in` mounting on the car a gear-Wheel engaging a side rack and in providing a special form ot' lockingarm for the gear-wheel, the novel features of which will be hereinafter fully described in the specication and deiinitelyponted outintheclaims; also, in rendering the locking-arm adjustable in relation to the gear-wheel, so that it can be brought into a close relation to the cogs of the latter in any season and be rendered independent of changes due to temperature or constant usage.

In the accompanying drawings,which illus- 5o trate my invention as applied to a passenger elevator-car, though of course it is applicable to any form of car that is raised and lowered from different horizontal levels, Figure l is a front elevation, with part broken away, so as to better illustrate the locking mechanism, of an elevator-car provided with my improvements. Fig. 2 is a detached view of one side of the car, showing the locking devices on a larger scale.

The hoisting-cable P is connected by a suit- 6o able pin, C, to two pivoted levers, FF, in the car, hung on suitable bearings, E E. These levers are slotted at their inner ends, so as to permit them to spread sufiiciently when the hoisting-cable yields through its being broken or through a giving way ot' the elevating ma chinery. To suitable supports on the top of the car are attached springs bearing on the levers. The springs are normally compressed.

I have shown a leaf-spring, M, and a spiral spring, N, for each lever. Either would be sufficient if made of great resiliency; but by providing more than one an additional guard against accident is furnished. Each lever` F carries an arm, G, (see Figs. 1 and 2,) pro- 75 vided with a screw-thread at its end, and a link, H, having threaded apertures in its ends, engages the end of arm G and a pivoted threaded rod, I, attached to alocking-arm, K. This locking arm is somewhat likea stirrup 8o pivoted to a bearing aboveagear-wheel,D,and between the rack A and the inner eXtreme point of the gear-wheel. By pivoting the lockingarm at such a point a maximum efficiency when said arm is under tension is secured, since the engaging-face of the locking-arm is not forced away from the cogs, as it would be if pivoted at a point outside of a vertical line cutting the wheel. Moreover, the strain on the arm itself is purely tensile, whereas there 9o would be a tendency to buckle if the pivotal fpoint were outside of the specified vertical.

The gear wheels D D are secured in bearings on each side of the car, and engagethe vertical racks A .A,secured to the guide-bars B B of the 9 5 car. By turning thetake-up links H H adelicate adjustment of the locking-arms KK with reference to the wheels D D can be made. The two arms of each lockingarm K K lie partly over the gear-wheel, and the transverse por- 10o tion or web at the free end of eaeh is nor- I mally adjusted so as to just clear the gearl wheels. Fliese locking-arms are made ofi wrought-steel or other metal havinggreat tenl sile strength, and the i'aee which engages the l cogs of the gear-wheels when the locking-arm l is in aetion is given an inclination such that it will lie parallel with the beveled tip ol` the i eogs ofthe gear-wheel inorder that the slightest depression of the loekingarni will cause 3 a firm lock ol` the gear-wheel. l

The operation of the locking arni will now il be understood. The elntching-webs ol the g locking arms or stirrups K K are adjusted by l turning the linksI'IlI until the websjust elcar l the eogs ol' the gearwheels. A cheek-block, Q. secured to the top ofthe elevator-,prevents l the locking-arm being pulled far l'roin the cogs of said gear-wheel when great weight is being Carried,V and also prevents straining of E the springs M N. ll', now, the hoisting-cable should break or give way,tlie springs would be l'ree to act, and by reason of the close adjustment of theloeking-arins the eogs ofthe wheels' .D D are instantly engaged. l have l'ound in l practice that a movement o one-sixteenth ot' an inch is snllieient to canse a firm engagement of the locking-arm, and have repeatedly released a car carrying two thousand pounds, the elevator-not sinking more than one-fourth of aniueh. It will be seen, therefore, that this sudden arrest insures sal'ety to all the parts. I have shown the car provided with a looking-` arni for each rack. WhileI prefer this strueture, a single locking-arm might serve the de sired purpose.

Having thus l'ully desi-ribed lny invention, whatI claim, and desire to secure by Letters Patent, is-

1. rlhe combination ofan elevatorear, aside rack parallel to the line of travel of the ear, a gear-wheel mounted upon the carin operative relation to the 1ack,an adjustable locking-arm carried by the ear and adapted to lock the gear-wheel, but nornzally out of engagement therewith, and lneans for shifting said arm. into engagement with the gear-wheel when the ear is released l'roni its hoisting devices.

2. The combination of an elevatorlear, side racks parallel to the line of travel ofthe ear, wheels carried by the ear gearing with said raeks,an adjustable locking-arm foreach wheel normally lying tangential to the wheel,eonnee 1 tions between each locking arm anda hoisting-cable, whereby it is normally held out of 5:,

engagement with its wheel, and means forgiv ing it a radial thrust toward the wheel, so as to engage the saine when the cable suddenly yields.

3. The combination of an elevator-car, side racks parallel to the line ol' travel ot the ear,

wheels carried by the car gearing with said raek, a safety locking-arm for each wheel pivoted on a vertical line cutting the wheel, the engaging-face of the loekingarin being in clined with relation to the eogs, so as tofirnily engage the top of the oog when brought into aetion, connections between each loekingfarlu and a hoistingcable, whereby the looking-arm is held normally out of engagement with the wheel,and springs l'or throwing it into engagement when the cable suddenly yields.

fl. The combination ofan elevator-car, side racks parallel to the line of travel of the car, gear-wheels D D, secured to the car,engaging the racks, adj uslable locking-arms K K, having engaging-webs, levers F F, springs engaged by said levers, a hoistingfcable connected to said levers, and a cheek above the levers to prevent undue strain on the springs.

In testimony whereof I alx my signature in presence of two witnesses.

JAMES V. DUS'DIN. 

